(1) Technical Field
The invention relates to a material handling container of the type for packaging, shipping, and inventorying goods. More specifically, the invention relates to a reusable, molded thermoplastic container which is collapsible when empty and stackable in either the collapsed or upright position in order to reduce the space required to ship or inventory goods stored in the container.
(2) Description Of The Prior Art
Material handling containers used for packaging, shipping and inventorying goods are well known in the art. For example, U.S. Pat. No. 4,591,065 issued to Foy on Mar. 27, 1986; U.S. Pat. No. 4,917,255 issued to Foy et al. on Apr. 17, 1990; U.S. Pat. No. 4,923,079 issued to Foy; U.S. Pat. No. 4,674,647 issued to Gynge et al. on Jun. 23, 1987; U.S. Pat. No. 4,775,068 issued to Reiland et al. on Oct. 4, 1988; and U.S. Pat. No. 5,094,356 issued to Miller on Mar. 10, 1992 all disclose collapsible containers having a base and four walls which are hingedly connected to the base. The walls are moveable between a collapsed position where the walls are folded one on top of the other and an upright position where the walls extend vertically upward from the base to define an interior of the container.
Each of the containers disclosed in the patents listed above include structure at the juncture between adjacent walls which help hold the walls together when the walls are in their erect and upright position. For example, the Foy et al. '255 patent discloses a series of delta shaped tabs on the sidewalls which are received by corresponding openings or sockets on the end walls when the walls are in their upright, erect position. The tabs are molded so as to create a corresponding series of depressions on the opposite side of the sidewall from the tabs. When the container is in its upright position, these depressions form irregular surfaces on the interior of the container.
Large collapsible containers of this type have potential use shipping liquid in bulk via a liner disposed in the container. However, irregular surfaces on the interior of the container can cause the liner to tear and the liquid to leak. Thus, there is a need for a container having structure at the adjacent sidewalls which can effectively hold the walls together and which maintains a smooth planer surface on the interior of the container when the walls are in their upright position.
The subject invention overcomes all of these deficiencies in the prior art and meets the above-identified needs in a durable, light-weight, container which can be molded using common tools with shorter cycle times and is capable of successfully handling liquid in bulk.